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Tuesday, April 26, 2011

This post is a deviation from my normal style of posting, but I feel that some things need to be said. The big news is the Fukishima power plant problems in Japan. First off, I'd like to explain that I was a certified nuclear engineer and power (steam) plant mechanic in the U.S. Navy years ago. I do see a place for nuclear power on subs and surface ships, but I'm not a fan of civilian based nuclear power. I believe solar and geothermal show much more promise without all the dangers. That being said, I'd like to discuss a few items of interest I've been hearing on the net.

What about the MOX fuel? One particle of Plutonium will kill you because it is the most radioactive substance on the planet.

I'm not sure where this myth started. Perhaps because people hear about Uranium all the time and not so much about Plutonium, that it sounds more exotic and powerful. It is true that for a given amount of Pu-239 and U-235, the Plutonium would be much more radioactive. They both decay with close to the same energy (sort of) but they have much different half lives. Pu-239 is about 24,000 years while U-235 is about 700,000,000 years. That means that Pu-239 will decay and release radiation 29,000 times more often than U-235. So, for a given amount stuck inside your body, the plutonium would be many times worse.

But lets compare with something else like Pollonium 210. Po-210 comes from Uranium and Uranium exists in small quantities in the earth's crust and a lot more exist in phosphate fertilizers. So, all the food we eat has Uranium in it, but it also has Po-210. Po-210 has a half life of 138 days which means it decays 1.8 billion times more often than enriched uranium and 63,500 times more often than Plutonium 239!

Luckily, we have adapted to trace amounts of radiation in the air, food, and water. But we haven't really adapted to the levels of radiation we get by fertilizing with phosphates. To make matters worse, people smoke tobacco that was grown with these fertilizers and the Po-210 gets lodged in the tar and stays in the lungs longer than it should. The body will get rid of it after a few months, unless that person continues to smoke.

I'm not saying that radiation is good, I'm saying that smoking is bad and people don't seem to care about smoking, or pollution, or living near coal plants. But they seem to be freaking about Fukishima. I'm just trying to stop the fear mongering and focus on the things we should really be afraid of.

Acid rain, oh yeah. Didn't it turn out to be no big deal?

Well, the media certainly doesn't talk about it anymore. But in actuality, it could be one of the biggest stories of the century with incredible ramifications to the health of the planet and the life it supports.

All plants have a root system that absorbs nutrients from the soil. The trick is, they only absorb water soluble substances. Aluminum exists in the earth's crust at about a 7% concentration. It is either oxidized or part of a salt of aluminum and therefore not water soluble. But when the rain is slightly acidic, it will dissolve the oxide layer on the aluminum and make it temporarily water soluble. Since aluminum is toxic to plants, you can see the problem. If you have seen the movie "The Road", you know where I'm going with this.

All the excess CO2 from burning fossil fuels and the sulfur from burning coal is making sulfuric acid and carbonic acid (among others) in the rain. Another problem is the uranium naturally occurring in the soil. It oxidizes as well and isn't water soluble until the acid rain hits it. So, with all our pollution and acid rain, we are getting far more radiation in our food, air, water, and cigarettes than our grandparents did. Enough said about that.

Fukishima has been pumping out radiation for a month straight and the west coast of North America is heavily contaminated now.

These data points were measured on Salt Spring island. Notice the slight spike on the 21st of March. This was just over a week after the tsunami in Japan. Why didn't the readings stay elevated if huge amounts of radioactive particles were streaming out of the reactors?

Here are some graphs from Berkley for Cs-137 and I-131 in rainwater.

Notice that the spike happened on March 23rd, just after the Salt Spring island spike. Also note that the readings have been steadily going down to minimum detectable levels. Also note that on the Berkley site it says that at the peak for the Cs-137 you would have to drink 4,000 liters or about 1,000 gallons of that water to get the same level of radiation as one would get in a round trip flight from San Francisco to Washington D.C. I would worry more about the I-131 because it concentrates in the Thyroid gland which is about 1300 times smaller than a 180 lb person. Their chart says 136 liters to get the same radiation, but really it would be about a tenth of a liter. But I-131 has a short 8 day half life, and as you can see from the charts, not much is making it over here.

I also found a German site with some Fukishima power plant numbers.

And finally we have this site (Norwegian) and it shows Xenon 133 everywhere. Admittedly this looks bad.

But this is total column. It shows the total radiation as expected from the ground to the sky. Not that useful to us humans, so next I look at surface contamination less than 100 meters.

So, the fear mongering videos show the first images but not the more down to earth surface contamination predictions. Here is one they really don't want you to see, I-131 surface contamination.

That's right. Nothing shows up. From all of the above graphs it is obvious that there was some meltdown and radiation leak. But the pockets of fissioning must have slowed way down. The danger to North America is almost non existent at the moment. But that could all change very quickly. But even if it does change for the worse, the level of dilution by the time any particles get over 6000 miles across an ocean would bring the levels down close to background normal or less in some cases. It is kinda like one person spraying some hair spray at one end of a football field and someone at the other end worrying about getting hair spray in their eyes. Even with a good wind, it just aint gonna happen.

On April 5, the estimated amount of radioactive materials released from Fukushima I Nuke Plant was 0.69 terabecquerels/hour for iodine-131 and 0.14 terabecquerels/hour for cesium-137. When the numbers were recalculated according to the INES method (converting cesium amount into iodine equivalent), the amount released turned out to be 6.4 terabecquerels/hour (which was 154 terabecquerels per day.

That was the new story, but I have a problem with the way they convert Cs-137 to I-131 equivalent. I-131 has a 8 day half life and Cs-137 has a 30 year half life so they say the Cs-137 is 1300 times worse. But even though it is in the environment 1300 times longer, it decays 1300 times less often. In the body Cs-137 only has a 70 day biological half life because the body will eventually get rid of it. I-131 pretty much stays in the thyroid. By the way, the thyroid is about 1300 times smaller than the whole body of a 180 lb person. And Cs-137 has more power per decay. The net result is that I-131 is actually about 100 times worse in the body for a given amount. In the environment, for a short time, I-131 is over 800 times worse than Cs-137. After about 40 days almost all the I-131 is gone and you are left with Cs-137 in the environment.

Another way of looking at it is if you had just enough I-131 to give you cancer in the environment and you had the same weight in Cs-137, the cesium would be there for 150 years but at 1/100th the radiation effect in the body. And you could injest that level your whole life and never get cancer from it. I'm not saying Cs-137 is good, I'm just comparing it to I-131. And I think the conversion to Iodine equivalent is bogus. They should have just reported the numbers separately to avoid confusion.

Conclusion

People in North America worried about drinking the milk with radioactive iodine should worry more about drinking milk after the acid rain just made the grass more radioactive. Remember, acid rain makes uranium and pollonium temporarily water soluble and the roots will absorb it.

And people should worry about living downwind from a coal burning plant. Heavy metals and radioactive isotopes occur naturally and it is in coal as well. We burn it and that junk gets in the air. You get more radiation from a coal power plant than you get living next to a nuclear power plant.

And worry about smoking. I know your grandparents smoked until their 80s before they died. But we have more phosphate fertilizers and way more acid rain. The cigarettes of today are many times more radioactive than 50 years ago.

So, stop the fear mongering and focus on reality. There are legitimate things to worry about, but the radiation fear should be focused on Japan, not North America. .....At least for now.

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